Various kinds of herbicides have been developed so far and have contributed to agricultural productivity and laborsaving. However, since there are some kinds of herbicides which have been used so many years, some weeds have become resistant to them and hardly destroyable weeds against which those herbicides are not or little effective have been increasing and therefore, it has been highly expected to develop herbicides having a wide herbicide spectrum and effective even against these hardly destroyable weeds.
Further, conventional herbicides often cause pollution of soil and ambient environmental pollution and, in order to prevent such environmental pollution, development of herbicides highly active and effective even in a small amount of use has been desired.
Besides, to deal with uneven propagation of weeds for a long period, herbicides excellent in residual effectiveness, effective even by dispensation in a wide range of periods before development of weeds until the growing period and having a wide range of proper dispensing time have been expected to be available.
Moreover, it is well known that with respect to use of conventional herbicides, phytotoxicities are sometimes caused on cultivated plants depending on a variety of factors relative to weather conditions such as temperature, wind, light, and the like; soil conditions such as soil properties, organic compound contents in soil, and the like; planting management conditions such as shallow transplantation depth, use of fragile and too long seedling, deep water control and the like; chemical agent dispensation conditions such as uneven spraying, excess spraying of herbicides and the like, appearance of herbicides highly safe and free from a risk of occurrence of damages on cultivated plants in any conditions has been desired.